Method of and apparatus for leaching



Feb. 24, 1931.

J. M. COAHRAN METHOD OF AND APPARATUS FOR LEACHING Filed June 9, 1927 iPatented Fel).l Z4, 129.31

JESSE M. coAHRAN, or sMEriIronT, rENNsYLvANI METHOD or am) APPARATUS ronLEAcHrNG Y f' In bmy application for patent SeriallNo; 175,734: ledMarch 16, 1927, is disclosed and claimed a method of counter-currentflow treatment wherein the ratio of volumes of thetwo interactingmaterials isso kvaried during the-treating operation as to produce themost complete results on both materials, and as' illustrating theinvention an apparatus particularly suitable for extracting'chemical Apconstituents of oneliquid by the use'of a liquid solvent for suchlchemicals is .shown and. described.'A In that-apparatusthe ratio of iliquor 'froml which constituents are to be eX- tracted toextractingagent is varied, whereby 115 the more completelyfextracted 'liquor' isbrought into'intimate contact with a relatively large volumeofsubstantially-fresheX- tracting'fagent thus to extract as much aspossible of thechemical therefrom, and theeX- racting agent more highlycharged with the chemical is brought-into initimate contact with arelatively large volume of substantially fresh or untreated liquor sothat the chemical in the solvent at the end of the trleating action maybe concentrated as poslsi le. l l

The present invention Yrelates to thelapplication of the same general'method to .extraction from solid material reducedto a sufficientlygranular or pulverulent condition so that it may be progressivelyrelated to the solvent sufficiently intimately for the solvent to actthereon, and has to do not only with the method as adapted to such.material, but o also to an apparatus particularlydesigned topracticethis method in connectionr'with such material. v

This invention has application commericallyin various industries, as forexample, inthe extraction of oils from seeds and nuts usually crushed orreduced to meal.

For a more complete understanding ofthe invention reference maybe had tothe accompanying drawings in vwhich* Figure-1 isa side elevation partlyin section of one form of apparatus embodying theyinvention. Y l vFigure 2 is an enlarged detail central vert-ical section through theupper portion of the Application met June-e,- iszv; serial No.'197,e6o.-

spaced treatingqcolumn showingzmojre particularly 'Y' the bearingV for acentral shaft..

line 3*,3 of Figure'fl.l Y y 1 Figure Ltis a fragment-ary sectionon line55 Figure 3 is 'an enlarged detail :section on t-of Figure-3- e Y fReferring to Figure 1', at 1 and 2 areindicated apair ofsuperposed-hoppers for containing the material to begextracted whichshouldbe'reduced, as by crushing or 4pther- 60 wise, toa suiiicientlygranular p ulverulentV lcondition so that the solvent may act'readilythereon.

y `Between these hoppersjlra'nd 2i's',y avalved connectionvf.- andthe'hopper 2 has a similar v65 valved connection with-a horizontalA pipe5 containing a -feed'screw 6. Thevalve connections 3 and 4-permit thehorizontalpipe 5v tobeclosed oft' from the atmosphere at all Vtimesthrough permitting the material to be ,70

extractedkto be fed into the hopper 2- in. batches as required. lVlhenthe materialv is being fed linto the hopper 2 thevalvel at4 4`is closedand the valvevat 3 opened. When the hopper 2 is full the valveisclosedfand the .75

valve-at et openedso that the material at'the hopper 2l may pass intothe piper. vThe feed screw 6 conducts the material past thel valve Y at4 into theupper portion. of a receptacle, herein shown asl consistingofv a f vertical column 7. Above the pipe 5 this columnv? is providedwith a screen 8 extending thereacross and of sufliciently ne meshvorhaving sufliciently 'smallperforations to prevent the materialbeing-treated from .passing therethrough, Below'the pipe 5 "andvertically from the screen 8 is a screen 9 shown 1 asof generallyconical shape having a centralv downwardlyextending tubular ,portion 10Within which is arranged a'conveyor screw 11 90 fixed to'fa vertical:shaft 12 positioned "coaxially, finA the column 7. The screens 8 and 9form between them a chamber 13 which is maintained substantially full ofthe material to be ez'rtracted so as to maintain therein fa 95relatively large volume of substantially untreated material from whichkthe material is fed ybymeans of the screw conveyor lylat Aal relativelyslow rate;`

. As lshownbest ini-Figure 2j the shaft `1.00

passes through the upper end wall 14 of theV column where there `ispreferably provided a packing gland 15 to prevent the escape of solvent.or vapors from the interior of the column therepast, and above the top14 of the column is arranged a supporting piece V16 hav-ing'afthrustbearing'17.' This thrust bearing 17 contains abearing ring '.18 on whichride rollers An oil retainer -20 threaded into Vthe member 17. is,positioned bearing member 23 which rests on a bearing ring 22riding onthe roller` 19, the vertical parts, is positioned alball bearing 210which takes the lateralpullofthe driving belt.

f Beneath the screenl extension 10 the shaft 12 may 4find bearing in aspider 30 having arms 31 spacedto permit the solid material`fed'throughthe portionbythe conveyor screw 11 to fall on to the upper ofa'series of rotary baileplates 32 liked to the shaft 12. The lower ofthese rotary baflies is positioned considerably above the lower end ofthe column, andthe lower end of the shaft 12 is rotatably mounted in astep bearing 35 carried v by a spider A36. By vertical adjustment of theshaftl section 21 the-vertical position of the rotary baffles may beadjusted as desired, the stepbearing 35 in normal servicetaking11o-weight, but serving to support the rotating parts when repairs to`the upper portion of the mechanism may be necessary. No lubrication forthis bearing is required.

'As shown best in Figures 3 and 4,'V each of the rotary baies 32 is ofgenerally conical shape, being downwardly inclined toward its downwardlyflanged outer edge from a flanged central opening at 40, the flange at40 being Afastened to a sleeve 41` fixed t-o rotatel with the shaft 12as by means of a bolt 42. The upper and lower faces of the bafflejmayfhave fixed thereto, radiallypositioned the` angles angles 43 and44, which not vvonly stiffen the baliie, but actas stirrers, the .upperangle 43 tending to carry the` materialfalling thereon around the axisof the shaft 12 before it escapes over the outer edge of thebaiile 'andy 44 on the under side actingV similarly on the upwardlyiiowing solvent,as will later appear. VBetween each pair of adjacent rotary baffles 32are positioned the stationary are frustoconibaffles '50. These, asshown,

51 which may be cal, having-marginal fianges made fast to the inner wallof the column and central openings 52through which the shaft Vwhichcarrythem pers I'60 and 12 passes and of sufficiently greater diameter thanthe shaft to permit the solid material to pass therebetween. Preferablythe stationary bafies are perforated with holes small enough to preventthe passage of the solid' material therethrough but which permit thesolvent'to pass upwardly therethrough tending to dislodge and ioat on'any solid materialwhich might tend to stick on their upper faces. withinthe series of rollers 19; A vcentral l' shaft section 21 isslidablyliey-ed to-an upper.

As'has before been noted, the `lower rotary tbaffle 32 .is positionedconsiderably abovethe This provides a v lower yend of the column.substantially open chamber 55' between the vlowest rotary baffle and thefrusto-conical base 56'of the column, this chamber providing'a spacewhich is lkept full of substantially fresh solvent which is introducedinto' the base of the column through'the pipe 57 i Vr`rl`he solvent isintroduced through this pipe` at such a rate as to-cause a relativelyslow passage of the -solvent upwardly ithrough' the column past andthrough the'"stationary baflies '50"and around the rotary rbaffles 32, Y

then up through the screenY v9 A'and through Ythe relatively dense'massofsubstantially un'- treated solid material in=the chamber 13, throughthe screenI pipe 7 O.v v 1f desired the shaft'12 Vmay be pro.- lvided,with scraping armsksuchas.` 75, 76. 'sweeping over the surfaces of thescreens 8 and 9 to prevent them from becoming clogged 'by the solidlmaterial. The solvent'above the chamber 55 fis in intimate' contact withVthe solid material passing downwardlyA Vwhich is in such separatedordiused condition that aV veryintimate contact between the solvent and`eachv particle of' theosolid lmaterial is effected, and as the solventbecomes more highly charged with the extracted material and is aboutto'be withdrawn, it passes up in diffused condition through therelatively large volume of substantially fresh material, thevolumetric'ratio ofsolvent to material being maintained relatively small so thatits concentration may be rendered as great as possible before it isdrawn off. The particles of solid material on the other hand, pass downthrough the column in diffused condition and ina tortuous passage pastthe baflies, more orless in circulation around the central axis of theVshaft 12 and when they pass from the lowest baille they fallin the samediffused or separated condition through a relatively quiescent body ofsubstantiallyfresh solvent of relatively large volume the chamber 55,where'the volumetric ratio of solvent to material is maintainedrelatively large. They settle down through this relatively largeV massVofv substantially fresh solvent into the frusto-conical base 56 ofthe'column from-which 'they are drawn offA through either of the valvedpipes '553 land 59 into the corresponding hop- 161. When either vofthese' :hop-

8 and-out through the I pers is beingV filled, the connection to the Yother hopper is closed off by means of its valve, and a valve connectionfrom its lower end is opened into the ytube 6,5 where a worm conveyorfacts to remove it for further treatment. l

vIt will be understood that the material thus substantially freed fromits content soluble in the solvent may then be treatedl in any suitableWay for the recovery of the solvent which it may ,still contain and thatrthe solvent containing the constituents dissolved from the material maybe treated VVfor the separation of the solvent for re-use and therecovery of the constituents removed thereby. vThe methods and apparatusfor by the appended claims.

I claim: Y

1. The method of extracting from fluent solid material which comprisesmaintaining a relatively large volume of'such material, feeding suchmaterial from said volume at a relatively slow rate and in diffusedcondition, maintaining a relatively large volume of substantially freshsolvent, effecting flow of solvent from said large volume in intimatecountercurrent flow tothe solid material fed from said large volume ofsuch material, causing said solvent thereafter in diffused conditiontopass through said large volume of such Vmaterial while maintaining thevolumetric ratio of solvent to material relatively'small, and removingit together with the substances extracted, causing said material to passthrough said relatively large volume of'solvent in diiiusedconditionwhile maintaining the volumetric ratio of solvent to material relativelylarge, and then removing the extracted material therefrom.

2. An apparatus of the class, described comprising a treatingreceptacle,smeans for maintaining a relatively large volume of uentsolid material at one end of said receptacle, means for maintainingarelatively large volume of solventat the opposite end of saidreceptacle, means for passing fluentsolid mate- Y Y rial in diifusedcondition from said large volume of solid material `through saidreceptacle and through said large volume of solvent while maintainingthe volumetric ratio of solvent to material relatively large, and meansfor passing solvent from said relatively large volume of solvent incountercurrent How to and in intimate contact with theV solid materialin said receptacle, and then in diffused condition through saidVlargevolume of solid material. Y

3. An apparatus of the class described commaintain af relatively largevolume of matevolumeupwardly through said column fand yby" said` shaftbelow said cover, v1on1-thev upper yof which the materialV drops `Vfromsaidfconveyor, said rotarybaliles having their outer ftionofsaid columnbeing free'from baflles to provide a largesubstantially unobstructedprising afcolumn, apair ofspaced screens in the upper portion'f'of.sai'dicolumnfdeining a chamber therebetween, .means for f feedingAfluent solidVl material Sinto saidvv chamber to rial therein, meansAfor conducting material through saidalower screenand-passing .it in idiffused` condition downwardly through.- said e column, Vmeans forremoving. said material from the lower end of said column, means foradmitting solvent tothe lowerend of said column above said removingmeanstomainf tain a-relatively large'volume of solvent there'- in.yand-` f.or v:passing said solvent from said diffused condition throughsaid chamber, and Vmeans'4 for;v removing the solvent from above theupper of said spaced screens. l

4L., An apparatus lof the class described come' 'prising` a column,a-.pair of spacedscreens in kthe upper` portion'` ot saidv column'vdefining.. a chamber f therebetween, s. means for `rfeeding Yfluentsolid material into said? vchamber to maintain a relativelylargevrvolume ofl such material therein, a shaft-arranged vertically insaidcolumnfa screw conveyor carried .by

said .shaft and extending through thedlower of 1said screens andacti-ngasthe'shaftvr is.. rotated to feed vmaterial downwardly from saidchamberra kseries of lconlcal'baffles-;carr1edV edges lower than Vtheircenters, stationary fruisto-conical battles positioned between Said arotary'bales and inclined downwardly toward .their centers and havingopeningsat said centersto-'permit -said materialto pass downwardly aboutsaid shaft, :thelower porvspacethrough which said'material may pass -indiffused condition from the lowermost baf-` ffle, means,for-removingsaid material from the lower portion of said space,-means for supplyingsolvent tolsaidlspace' `to provide a relatively large volumethereinthrough which said material -passes,and to pass up-v wardly around saidbaffles and Lin diffused condition through said chamber, meansfforwithdrawing lsolvent from above the upper of said screens, and means forrotating said shaft.

5. An apparatus of the class described comprising a column, a pair ofspaced screens in the upper portion of said column defining a chambertherebetween, means for feeding fluent solid material into said chamberto maintain a relatively large volume of such material therein, a shaftarranged vertically in said column, a screw conveyor carried by f saidshaft and extending thro-ugh the lower of said screens and acting as theshaft is rotated to feed material downwardly from said chamber, a seriesof conical baffles carried by said shaft below said cover, on the upperof which the material drops from said conveyor, said rotary bailieshaving their outer edges lower than their centers, stationary frustO-conicalzbailies positioned between said rotary Y Y '5 bailies andinclined downwardly toward their centers and having openings at saidcenters .to permit said material to passdo-wnWardly about said shaft,certain of said baiiles having radial ribs thereon and certain beingperforated for. the passage of solvent therethrough, the lower portionofJsaid column beinglfree frombaiiies to provide a large substantiallyunobstructed space through which said material may pass in diiusedcondition from the i lowermost bafie, means for removing said materialfromV the lower portion of 'said space,fmeans for supplyingsolventtosaid space to provide' a relatively vlarge volume thereinthrough which said material passes,

,20 and to pass upwardly around said baiiies andl in diiiused conditionthrough said chamber, lmeansv for withdrawing solvent from abovetheupper of'said screens and means for rotating said shaft. o 'Y Y t c u6. An apparatus of `the `class described comprising apair of superposedcommunieating valved hoppers, a column, means for continuously feedingfluent solid material from the lowerofsaid hoppers to the.- upperportion of 'saidcolumm meansfor vmaintaining a relatively large volumeof such material in ther-upper portion of said hopper and for causingsuch material to pass Ydownwardly through said columnin diffusedcondition,- a

' 35 plurality of receptacles, means for'collecting the material passedthrough said column into any `of said receptacles at will and forshutting 0E communication of theremainder of said receptacles from saidcolumn, means for l o causing said material to pass in diffusedcondition through a relatively `large-volume of solvent before beingremoved from said column, and for causing solvent lfrom said volume topass upwardly inv intimate contact ,T with the diffused material and indiiiused 50 signature.

condition through said large volume of such material, and means for thenremoving said solvent from said column.

In testimony whereof I have affixed my JESSE M. GOAHRAN."

